spf-discuss
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RE: SPF & proxy filters

2004-09-10 20:48:18
On an un-related subject...
Does you firewall know what users are valid?
Or does it just accept email for anyone, then forward it to your SMTP
server?

If it accepts email for anyone, then the sender/spammer will never drop an
invalid email address.

I had this problem at the office.  When someone would quit, the spam (or
whatever) would continue for years since it was accepted by our email
forwarder.  The next hop would return an error, but that seemed to not count
for much.

The good spammers will drop you off the list if they get an:
        ERROR:5.7.1:"550 ..." (or similar)

Guy

Anything I say is my opinion.
Anything you say is your opinion, in my opinion. - "Guy Watkins"

-----Original Message-----
From: owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
[mailto:owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com] On Behalf Of Kevin 
Peuhkurinen
Sent: Friday, September 10, 2004 2:49 PM
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: [spf-discuss] SPF & proxy filters

Hi all.  Forgive me if this has been discussed before.   I'm sure it 
must have been, but I cannot find anything useful in the archives.

My problem is that for security reasons, all incoming email is first 
recieved by my Checkpoint firewall's SMTP Security Server.   It is then 
handed off to my Exim/SpamAssassin box.   I want to have Exim run SPF 
checks on the incoming mail and add the SPF headers.   I am not at this 
point interested in enforcing any sort of policy, I just want the 
headers.   The problem, of course, is that while Checkpoint preserves 
the envelope headers, the Exim box sees the sending IP and HELO as the 
firewall.   I'm thinking that A) I'm SOL in terms of the specifications 
and B) if I want this to work I'm going to have to kludge something 
together that extracts the IP address of the sending host from the 
recieved headers and calls spfd itself or (>shudder<) write an OPSEC 
compliant module for the firewall itself.

Has anyone else already dealt with issues like this?

Thanks,
Kevin

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